The First Riddle

The Riddle
Knock once for the hound of the sun.

Knock twice for the hare of the moon.

Three times for the vigilant one.

Four times too soon.

The hound swallows stars on his tongue.

The hare eats the heart of the moon.

The queen’s harp is never unstrung,

Never so soon.

Four times for the door in the hill.

Five times for the gold afternoon.

Six knows what she’s done, and still –

Too soon, too soon.

Speculation
The Hound and Hare refer to, respectively, the King and Luna Thorne. The vigilant one could refer to Anna, who's the main riddle-solver in the podcast and also commonly has to make deals in threes. Four is both considered a lucky and unlucky number, so that could have any number of meanings.

The queen's harp also has no confirmed meaning, though it could refer to Mabel, Anna's queen. The door in the hill is probably a reference to Anna's descent in episode sixteen. The gold afternoon could refer to one of Mabel's memories or Anna's monologue in episode fourteen. Six has always struck the author of this wiki as Aurora Silver (A-U-R-O-R-A is six letters, and she damn well knows what she's done), but using this logic, it could also refer to Monica or even the Martin name (both six letters).